IT34488: MQ listener runqmqlsr not accepting new connections and also consuming high CPU

APAR status

• Closed as program error.

Error description

• After unexpected termination (e.g. process killed by  user or
  the process ended
  unexpectedly) of an amqrmppa process, MQ listener process
  runmqlsr not accepting new
  connections and also consumes high CPU.
  
  The MQ listener runmqlsr trace had repeated failures with errno
  111 from connect  socket API.
  
   15:55:31.460322    34925.1           :       ----{
  xcsSetSocketAddress
   15:55:31.460324    34925.1           :        sun_path:
  /var/mqm/sockets/TEST/@qmpersist/spipe/host1/ccc.23506
   15:55:31.460326    34925.1           :       ----}
  xcsSetSocketAddress rc=OK FunctionTime=4
   15:55:31.460328    34925.1           :       ----{  socket
   15:55:31.460332    34925.1           :       ----}! socket
  rc=Unknown(8) FunctionTime=4
   15:55:31.460334    34925.1           :       ----{  connect
   15:55:31.460339    34925.1           :       ----}! connect
  rc=Unknown(FFFFFFFF) FunctionTime=5
   15:55:31.460342    34925.1           :            connect()
  failed errno = 111
  

Local fix

• Restart the MQ listener
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  Users using MQ channels
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  A defect in MQ listener in handling unexpected termination of an
  amqrmppa process
  could cause the process to go into an infinite loop and resulted
  in high CPU usage. The issue occurred when the process ID of the
  failed process was re-assigned to a new process before the MQ
  listener detected the failure, and so was only likely to be
  observed in environments with limited availability of new PIDs.
  

Problem conclusion

• MQ listener code has been modified to prevent the process going
  into infinite loop when an amqrmppa process terminates and its
  PID is reassigned.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.0 LTS   9.0.0.12
  v9.1 LTS   9.1.0.8
  v9.2 LTS   9.2.0.2
  v9.x CD    9.2.3
  
  The latest available maintenance can be obtained from
  'WebSphere MQ Recommended Fixes'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
  
  If the maintenance level is not yet available information on
  its planned availability can be found in 'WebSphere MQ
  Planned Maintenance Release Dates'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
  ---------------------------------------------------------------
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  IBM MQ BASE M/P

• Fixed component ID

  5724H7261

Applicable component levels